How Does A Lava Lamp Work?

The lava lamp has an illuminating bulb, a glass bottle which contains a transparent oil and translucent wax, and a metallic wire coil.

The glass bottle is placed on top of the bulb, which heats the contents. The metallic wire coil is hidden in the base of the lamp. The wax is denser than the oil at room temperature, and slightly less dense than the oil under warmer conditions. This is because the wax expands more than the oil when heated.

When the lava lamp is switched on, the bulb heats the bottom of the glass bottle and the metallic wire coil, which heats the contents of the glass bottle in the vicinity.

The wax at the bottom heats until it melts, and becomes less dense than the liquid above it. A portion of wax rises towards the top of the container. At the top, away from the heat source, the wax cools and contracts, and as its density increases, it falls through the liquid and back to the bottom of the container again.

A portion of wax may rise as another falls. The movement of the wax is unpredictable due to chaotic behaviour. Because of this, lava lamps can be used as a physical random number generator.

The wax gets hot rises and at the top of the glass container it cools and the density is increased and it starts to fall

Works like your mum in bed